This application is related to Japanese application No. HEI 11-370407 filed on Dec. 27, 1999, whose priority is clamed under 35 USC xc2xa7119, the disclosure of which is incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a dye-sensitizing solar cell, a method for manufacturing a dye-sensitizing solar cell, and a solar cell module.
2. Description of the Related Art
A solar cell of a silocon semiconductor using p-n junction or a solar cell including a semiconductor layer made of a metallic oxide such as a titanium oxide with a photosensitizing dye adsorbed on the layer has been so far generally known.
Such a solar cell having the adsorbed photosensitizing dye is generally called a dye-sensitizing solar cell.
Among solar cells, the dye-sensitizing solar cell has attracted much interest because of high conversion efficiency.
In a conventional structure of the dye-sensitizing solar cell, it is generally known that the structure is composed of a transparent substrate such as a glass, a transparent conductive film of SnO2 formed on the transparent substrate, a semiconductor layer of a titanium oxide formed on the conductive film, a conductive substrate opposing to the transparent substrate in spaced-apart relationship, a resin such as an epoxy resin for sealing peripheral edges of the transparent substrate and the conductive substrate to form a closed space between the substrates, and a redox electrolyte filled into the closed space.
When light is applied to the semiconductor layer of the dye-sensitizing solar cell, electrons are generated in the semiconductor layer, taken out in an external electric circuit to work and then transferred to the conductive substrate. The electrons transferred to the conductive substrate are further transferred to the electrolyte as ions, and returned to the semiconductor layer.
This is repeated to obtain electric energy from the dye-sensitizing solar cell.
In the dye-sensitizing solar cell having the conventional structure, the redox electrolyte is sealed with the resin.
When the solar cell is actually used outdoors, the surface temperature exceeds 80xc2x0 C. to expand the electrolyte therein.
Further, in consideration of the factor that the solar cell is exposed to the outdoor weather for a long period of time, the solar cell made by a method in which the redox electrolyte is sealed with the resin is problematic in durability. That is, when the epoxy resin is broken by weathering, the redox electrolyte is leaked. Thus, further improvement has been in demand for increasing durability and safety of the dye-sensitizing solar cell.
Under these circumstances, the invention is to provide a dye-sensitizing solar cell excellent in durability and safety in which the redox electrolyte is sealed with a vitreous material excellent in durability and chemical resistance, and a method for manufacturing the dye-sensitizing solar cell.
In accordance with the present invention, there is provided a dye-sensitizing solar cell comprising: a first substrate whose surface is at least conductive; a second substrate on which a conductive layer is formed, the second substrate being transparent, the first and second substrates being spaced by a distance with the conductive surfaces of the first and second substrates opposite to each other; a semiconductor layer having a dye adsorbed thereon, the semiconductor layer being formed on one of the conductive surfaces; a glass frit for sealing peripheral edges of the first and second substrates; and a redox electrolyte which is filled between the first and second substrates.
Also, in accordance with the present invention, there is provided a method for manufacturing a dye-sensitizing solar cell, comprising the step of: forming a semiconductor layer on a first or second substrate, a step of opposing; the first and second substrates to each other in spaced-apart relationship; sealing edges of the first and second substrates with a glass frit to form a closed space between the first and second substrates; forming openings for communicating the closed space with the outside in at least two positions; circulating a dye solution within the closed space through the openings so that the dye is adsorbed on the semiconductor layer; and discharging the remaining dye solution and then injecting a redox electrolyte into the closed space.
Also, in accordance with the present invention, there is provided a solar cell module comprising a plurality of dye-sensitizing solar cells are arrayed in a plane and electrically connected with metal wires, each of the dye-sensitizing solar cells being defined in the invention.